<?php

/*
 * This file is part of SwiftMailer.
 * (c) 2004-2009 Chris Corbyn
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * A basic KeyCache backed by an array.
 *
 * @package    Swift
 * @subpackage KeyCache
 * @author     Chris Corbyn
 */
class Swift_KeyCache_ArrayKeyCache implements Swift_KeyCache
{
	/**
	 * Cache contents.
	 *
	 * @var array
	 */
	private $_contents = array();

	/**
	 * An InputStream for cloning.
	 *
	 * @var Swift_KeyCache_KeyCacheInputStream
	 */
	private $_stream;

	/**
	 * Create a new ArrayKeyCache with the given $stream for cloning to make
	 * InputByteStreams.
	 *
	 * @param Swift_KeyCache_KeyCacheInputStream $stream
	 */
	public function __construct(Swift_KeyCache_KeyCacheInputStream $stream)
	{
		$this->_stream = $stream;
	}

	/**
	 * Set a string into the cache under $itemKey for the namespace $nsKey.
	 *
	 * @see MODE_WRITE, MODE_APPEND
	 *
	 * @param string $nsKey
	 * @param string $itemKey
	 * @param string $string
	 * @param integer $mode
	 */
	public function setString($nsKey, $itemKey, $string, $mode)
	{
		$this->_prepareCache($nsKey);
		switch ($mode) {
			case self::MODE_WRITE:
				$this->_contents[$nsKey][$itemKey] = $string;
				break;
			case self::MODE_APPEND:
				if (!$this->hasKey($nsKey, $itemKey)) {
					$this->_contents[$nsKey][$itemKey] = '';
				}
				$this->_contents[$nsKey][$itemKey] .= $string;
				break;
			default:
				throw new Swift_SwiftException(
					'Invalid mode [' . $mode . '] used to set nsKey=' .
					$nsKey . ', itemKey=' . $itemKey
				);
		}
	}

	/**
	 * Set a ByteStream into the cache under $itemKey for the namespace $nsKey.
	 *
	 * @see MODE_WRITE, MODE_APPEND
	 *
	 * @param string $nsKey
	 * @param string $itemKey
	 * @param Swift_OutputByteStream $os
	 * @param integer $mode
	 */
	public function importFromByteStream($nsKey, $itemKey, Swift_OutputByteStream $os, $mode)
	{
		$this->_prepareCache($nsKey);
		switch ($mode) {
			case self::MODE_WRITE:
				$this->clearKey($nsKey, $itemKey);
			case self::MODE_APPEND:
				if (!$this->hasKey($nsKey, $itemKey)) {
					$this->_contents[$nsKey][$itemKey] = '';
				}
				while (false !== $bytes = $os->read(8192)) {
					$this->_contents[$nsKey][$itemKey] .= $bytes;
				}
				break;
			default:
				throw new Swift_SwiftException(
					'Invalid mode [' . $mode . '] used to set nsKey=' .
					$nsKey . ', itemKey=' . $itemKey
				);
		}
	}

	/**
	 * Provides a ByteStream which when written to, writes data to $itemKey.
	 *
	 * NOTE: The stream will always write in append mode.
	 *
	 * @param string $nsKey
	 * @param string $itemKey
	 * @param Swift_InputByteStream $writeThrough
	 *
	 * @return Swift_InputByteStream
	 */
	public function getInputByteStream($nsKey, $itemKey, Swift_InputByteStream $writeThrough = null)
	{
		$is = clone $this->_stream;
		$is->setKeyCache($this);
		$is->setNsKey($nsKey);
		$is->setItemKey($itemKey);
		if (isset($writeThrough)) {
			$is->setWriteThroughStream($writeThrough);
		}

		return $is;
	}

	/**
	 * Get data back out of the cache as a string.
	 *
	 * @param string $nsKey
	 * @param string $itemKey
	 *
	 * @return string
	 */
	public function getString($nsKey, $itemKey)
	{
		$this->_prepareCache($nsKey);
		if ($this->hasKey($nsKey, $itemKey)) {
			return $this->_contents[$nsKey][$itemKey];
		}
	}

	/**
	 * Get data back out of the cache as a ByteStream.
	 *
	 * @param string $nsKey
	 * @param string $itemKey
	 * @param Swift_InputByteStream $is to write the data to
	 */
	public function exportToByteStream($nsKey, $itemKey, Swift_InputByteStream $is)
	{
		$this->_prepareCache($nsKey);
		$is->write($this->getString($nsKey, $itemKey));
	}

	/**
	 * Check if the given $itemKey exists in the namespace $nsKey.
	 *
	 * @param string $nsKey
	 * @param string $itemKey
	 *
	 * @return boolean
	 */
	public function hasKey($nsKey, $itemKey)
	{
		$this->_prepareCache($nsKey);

		return array_key_exists($itemKey, $this->_contents[$nsKey]);
	}

	/**
	 * Clear data for $itemKey in the namespace $nsKey if it exists.
	 *
	 * @param string $nsKey
	 * @param string $itemKey
	 */
	public function clearKey($nsKey, $itemKey)
	{
		unset($this->_contents[$nsKey][$itemKey]);
	}

	/**
	 * Clear all data in the namespace $nsKey if it exists.
	 *
	 * @param string $nsKey
	 */
	public function clearAll($nsKey)
	{
		unset($this->_contents[$nsKey]);
	}

	// -- Private methods

	/**
	 * Initialize the namespace of $nsKey if needed.
	 *
	 * @param string $nsKey
	 */
	private function _prepareCache($nsKey)
	{
		if (!array_key_exists($nsKey, $this->_contents)) {
			$this->_contents[$nsKey] = array();
		}
	}
}
